Weve used Elance.com and Guru.com for numerous different outsourcing projects beforehand, including sales.
To be honest though it does depend on location, having had salaried, salary + commission, commission only, remote commission only it really depends on the product and its location.
For example if you need a couple of calls to close a sale then its probably worthwhile to have regional specific sales reps (commision only) as it will probably end up the client wants to meet to close.
Price is also a big factor, try cold selling anything more than £100 ($160) over the phone and your gonna be up against it!
To be honest though it does depend on location, having had salaried, salary + commission, commission only, remote commission only it really depends on the product and its location.
For example if you need a couple of calls to close a sale then its probably worthwhile to have regional specific sales reps (commision only) as it will probably end up the client wants to meet to close.
Price is also a big factor, try cold selling anything more than £100 ($160) over the phone and your gonna be up against it!